Use Cases Introduction to Software Engineering Introduction

Benefits of Use Cases

• Use cases diagrams capture user-visible functions
• Identifying actors help capture who needs the system functionality
• Relationships between use cases document opportunities for reuse
• Use cases provide a basis planning and scheduling incremental development
• Use cases can provide a basis for system testing

• Coming up: In Class Exercise

In Class Exercise

• Lets create a use case diagram for
• iPod
• Television set
• Elevator
• ATM
• Online Scrabble game
• Word Processor

• Coming up: Use cases for CS421

Use cases for CS421

• Show system boundary

• Show Actors outside boundary

• Use extend, include, generalization/specialization where appropriate

• Typically one diagram for your project is sufficient

• Coming up: Use cases for CS421

Use cases for CS421

• For each use-case (oval) in your diagram include the use-case description text described in the slide for Chapter 5, titled:
• Use Case Description
• about slide #14

• Coming up: Questions

Questions

• Who might be interested in reviewing or using use case diagrams?
• When in the development life cycle should we employ use cases?
• What do use cases have to do with object-orientation?
• What level of use-case granularity is best?
• How many use cases are enough?
• Can other modeling activities help in discovering use cases?
• When in the development life cycle do we stop referring to or refining the use cases?
• What should the text description of use case contain?

• Coming up:

• Backup Slides
• The following slides were removed over time.

• Coming up: Extends vs. Includes vs. Generalization